This invention relates to article transfer mechanisms for machine tools or for other machines in which a plurality of movable articles are stored in a storage magazine and are selectively transferred from the storage magazine to an article support on the machine or vice versa.
In the past, the tool transfer arms for machine tools had to be clamped closed by a hydraulically or pnuematically operated cylinder during the time that the tool was being moved from the tool storage magazine to the machine tool spindle, or vice versa, or had to be held in place by spring clamps. One example of the former case is disclosed in U.S. Pat. No. 3,760,958, which was issued on Sept. 25, 1973, for a "CLAMPING TOOL CHANGER MECHANISM AND ACTUATING MECHANISM FOR A MACHINE TOOL." One example of the latter case is disclosed in U.S. Pat. No. 3,840,981, which was issued on Oct. 15, 1974, for a "TOOL CHANGE ARM GRIP."
The hydraulically orpneumatically operated clamps are, however, relatively expensive and are subject to failure of the fluid system and components thereof while the spring clamps are relatively limited in terms of the clamping force that they can provide and tend to weaken with use.
Accordingly, the principal object of this invention is to provide an article transfer mechanism which is simpler and less expensive than the prior pneumatically or hydraulically clamped mechanisms, which is capable of providing a constant clamping pressure which does not significantly diminish with use, and which is more reliable than either of the above-noted prior art clamping mechanisms.
Other objects and advantages of the invention will be apparent from the description which follows.